Sanding question

I am a real green thumb at body work so this will mostlikly be a dumb question. I am repainting my wifes 89 jaguar. It is red. Ok here is the question. I started sanding it down with an air longboard sander with 80 grit paper.(repairs have to be made).When first starting a area the dust from sanding is white, then after a few minutes it will burst red. I guess the red is the main color , but is the white dust the clear coat. If an area is not in need of body repair how far doI have to sand it down ...just ruff the clear coat or all the way into the color coat.

why are you sanding it with 80 grit on a air boad you are making more work for your self than you know . if the paint is good sand out with 320 wet with a block and prime sand out with 400 to600 wet and paint .get some how to books. sanding boads are good for filler and making ruts in the steel if you do not know that you are doing you may want to get some paint jobs under your belt be for you work on the jag .if you hit some glass or trim with that air boad it will coast $$ big time

Pat is correct. You are making way too much work for yourself. You can just wet sand that original paint if it's not all peeling and crappy and just fix your dents and patch them in primer and wet sand them as well.

there are a few cracks in the paint where I am sanding. I thought it would be like repairing a figerglass crack, in the way that you must remove the crack to fix it. I have been taking the area down to metal when I find a crack or deep bondo ( 1/4 +). However the roof and front and rear pan( grill bumper areas) are good and I will only wet sand them.
Since I will have bar metal , plastic fill and wet sanded paint , do I still use the etching primer then the sealer.
Do you guy's trust the body work of an unknown person on a car you bought? I mean if you were doing this job and found the cracks and lots of plastic where the panels could have been hammered out a little if not all the way. woulden't you take it down to the metal?

Yup, absolutely. Anytime I dig into someone else's questionable repair techniques, I would strip the whole car down to bare metal, Lord knows what else he has hidden there!!! I prefer putting filler on bare metal with a 36 grit finish on the metal to get good adhesion. Some folks put filler over etch primer, I like to get the nasties fixed, then etch prime everything....JMO

Old cars can be such fun! I just did a '57 Chevy that was kind of "wavy", and I suspected too much paint film, so planned on stripping it from the start.

As it turns out, it had EIGHT paint jobs on it!!! It also had a lot of bodywork. I ground out, and redid anything that looked suspicious, such as plastic filler that was used over paint. Today many products are okay over paint, but not filler THAT old!

You seem to be on the right track. The recommended maximum number of paint jobs is three (including the new one), unless you are going with black, or want a show finish.

you did not say any thing about thick filller and cracks? at this point yes dig it out . but i would not use a air boad . i would use stripper or a cup wheel on a grinder the metal may have been over sanded all ready and will get thin fast with 36 grit . if the body work is not good the prep is not good . i did this for a living for many years .i have seen filler put rigth over shinny paint and stick .on the new car you do not cut in to the steel with 36 grit you work the bent out sand out to 80 grit bust off the clear and fill with filler . why do you do it this way??? new car have anti corrosion coating on the steel and alot of the filler will not stick to it .the E coat primmer sticks better that why you do not cut in to the steel BUT sometimes you do then the new filler work good for this like Z grip the steel on new cars is junk it needs the corrosion coating on it to live cutting thru this invites rust to form

in spots the filler was very thin in others , like the area that started this thread I lost a nickel in it. No not flat I MEAN ON EDGE! What little I know about body work my dad tought me on my first car. A 1950 willy's war jeep...there was not a round corner on that thing and that long board keeped a young kid from tipping the DA on it edge, and thats a trouble spot for a lot of beginners I think. At least it was ( is ) with me. Thank for the help